The technology inside Apple’s $50 Thunderbolt cable

Using Thunderbolt peripherals so far requires a rather expensive cable that is …

The first Thunderbolt compatible peripherals—Promise's Pegasus RAIDs—started shipping on Tuesday. Using the RAIDs with a Thunderbolt equipped Mac, though, requires a rather expensive $50 cable that is only available from Apple. We dug into the design of the cable to find out why Apple felt justified in charging $50 for some plastic-wrapped copper wire, and why Thunderbolt may have a hard time gaining traction outside of the higher-end storage and video device market—a fate similar to Apple's FireWire.

Promise's RAIDs do not come supplied with a Thunderbolt cable. Instead, users are directed to buy a Thunderbolt cable directly from Apple, which costs $49 for two-meter length. We contacted Promise to find out why a Mini DisplayPort cable could not be used in its stead, since the Thunderbolt port is based on Mini DisplayPort. A support technician told Ars that Apple's cable is a "smart" cable that "has firmware in it."

Intel confirmed that Thunderbolt requires specific Thunderbolt cables. "Only Thunderbolt cables can be used to connect Thunderbolt products using Thunderbolt connectors," Intel spokesperson Dave Salvator told Ars. "The cables have been designed for the 10Gbps signaling as well as power delivery that are part of Thunderbolt technology."

Active cabling required

Apple didn't respond to our requests for further information about the "firmware in the cable," but an EETimes article from earlier this year noted that in addition to having different electrical characteristics from Mini DisplayPort, Thunderbolt also uses active cabling to achieve full duplex 10Gbps transmission.

A source within the telecom industry explained to Ars that active cables are commonly used at data rates above 5Gbps. These cables contain tiny chips at either end that are calibrated to the attenuation and dispersion properties of the wire between them. Compensating for these properties "greatly improves the signal-to-noise ratio" for high-bandwidth data transmission.

"Unlike ordinary passive cables that can be used at lower data rates, the unprecedented speed of the new Thunderbolt technology places unique demands on the physical transmission media," according to Gennum's website. "The GN2033 provides the sophisticated signal boosting and detection functions required to transfer high-speed data without errors across inexpensive Thunderbolt copper cables."

Our telecom source noted that Intel made an unusual choice in also using active cabling for future optical-based iterations of Thunderbolt. Passive cabling is more common, but active cabling could offer some advantages. For one, active cables could combine fiber optics with electrical cabling for power transmission. Another good reason to use active optical cables, according to our source, "is that your current electrical ports can be forward compatible with future optical cables."

So far, though, Apple is the only supplier for Thunderbolt cables. Though Gennum is already highlighting its Thunderbolt transceiver chips, Intel would not say when official specs would be released to other manufacturers, or when other suppliers might be able to offer compatible cabling.

FireWire II: Thunderbolt Boogaloo?

The unfortunate side affect of all this is that if you are interested in using Thunderbolt-compatible peripherals—including RAIDs, hard drives, and video I/O devices coming soon—you'll have to buy a $50 cable from Apple for each device. Without additional suppliers, that could lead to trouble in gaining wider adoption for the standard in the industry.

The situation is not unlike the one that plagued FireWire in its early days. Designed by Apple and featured on its own computers, the original FireWire 400 standard offered significant speed improvements over USB 1.1, could supply more power to peripherals, and used an architecture that allowed any FireWire device to communicate with another, making it possible to forgo the need to connect both devices to a host computer.

Despite these benefits, FireWire cost more to implement on a device because it required a separate controller chip in each device. And though Apple turned over the FireWire standard to standards body IEEE, the company originally required additional licensing fees to use the FireWire trademark and logo. This made USB a more attractive, less expensive alternative for device makers.

Apple later relaxed the licensing fees, but an alternate 4-pin, non-powered version of FireWire—dubbed "IEEE 1394" and branded as "i.Link" by Sony—had already begun to gain wide adoption. USB 2.0 improved speeds to be more competitive with FireWire 400, while retaining its cost advantage. A faster FireWire 800 standard emerged, but used an entirely new 9-pin connector that required adapters to use with 6-pin FireWire 400 devices or 4-pin IEEE 1394 devices.

The combination of non-compatible plugs and added cost meant that FireWire ended up being largely confined to high-speed storage and the burgeoning digital video and digital audio industries.

As mentioned previously, the devices featuring Thunderbolt that have been announced so far include a variety of high-performance storage and mobile video I/O devices. Thunderbolt's high bandwidth and low latency are perfect for these applications. But Thunderbolt's high cost in terms of the necessary controllers and relatively expensive active cabling could limit its expansion to the broader market.

Furthermore, Intel only mentioned two vendors aside from Apple who were considering adopting Thunderbolt when it announced the technology earlier this year: HP and Sony. HP ultimately decided it wouldn't be adopting Thunderbolt in its computers any time soon. Sony has announced a new Vaio Z laptop that incorporates Thunderbolt controllers from Intel, but uses a proprietary optical connection via a specially modified USB3 port. That port can connect to a special discrete GPU-equipped docking station that won't be compatible with standard Thunderbolt peripherals.

Thunderbolt may be capable of some impressive speeds, but Apple and Intel run the risk of the technology quickly becoming a dead end if Apple remains the only vendor for Thunderbolt-equipped computers as well as Thunderbolt cables. Greater third-party support will be the key to the broad market adoption needed to support Thunderbolt in the years to come.

266 Reader Comments

Apple is so schizophrenic right now. On one hand they are rolling out these high-end cables to speed up data transfer for audio and video applications. On the other hand they are repositioning their high-end video editing software as a relatively low-cost prosumer solution. Consumers are going to see little benefit from this new technology and enterprise customers who might adopt it are being alienated.

The cable costs 1/6th of a Final Cut Pro X license.

Keep in mind that FCP Studio used to be a VERY heavy box. All that paper, and shipping, and giving the cuts to distributors and dealers... Start doing a little internal math and youll probably come up that the current price, considering it's an extra 100 to get some other apps that were in the box, is probably just about in line.

In addition, moving the 'expensive' port electronics out to the cable makes the devices cheaper, which is A Very Big Deal. It means every user doesn't have to buy a fancy port, and only those users who need the Tb interface will pay for it.

Yes. It is cheaper for users who don't need TB. But, just as importantly, it's also cheaper for the users who do need TB.

It is cheaper to design/manufacture a transceiver tuned for one cable design than to design/manufacture a transceiver that can adapt to any potential cabling on the fly.

Can someone explain why they wouldn't just put the transciever chips in the host and peripheral, letting the cable be bare copper?

I don't know for sure, but an educated EE guess is that the transceivers handle the interface between the bare copper and the connector. This might seem a trifle, but at 10 GHz, connectors and the such behave quite wierdly... Just my guess. That and chips in cables are hardly a new concept (i.e. SCSI)

One more comment: I think people are getting overly worked up here. Apple always charges too much for cables. Since this is an active cable, it'll be more expensive than "just wires and connectors". However, if TB catches on in any meaningful way, then it's almost guaranteed that significantly cheaper cables will be available elsewhere.

Apple charges almost six times as much for a six foot Firewire 800 cable as Monoprice. Assuming the mark-up would be similar, that implies Monoprice might be able to sell a TB cable for about $8.50. If we knew Monoprice would have these cables at that price, would we even be having this discussion?

Even if we assume Monoprice could not achieve the same cost savings due to the active nature of the cable, maybe they could sell the cable for $20. Would we even be having this discussion if a TB cable were $20 instead of $50?

One more comment: I think people are getting overly worked up here. Apple always charges too much for cables. Since this is an active cable, it'll be more expensive than "just wires and connectors". However, if TB catches on in any meaningful way, then it's almost guaranteed that significantly cheaper cables will be available elsewhere.

Apple charges almost six times as much for a six foot Firewire 800 cable as Monoprice. Assuming the mark-up would be similar, that implies Monoprice might be able to sell a TB cable for about $8.50. If we knew Monoprice would have these cables at that price, would we even be having this discussion?

Even if we assume Monoprice could not achieve the same cost savings due to the active nature of the cable, maybe they could sell the cable for $20. Would we even be having this discussion if a TB cable were $20 instead of $50?

This assumes Apple/Intel will allow Monoprice or the like to manufacture Thunderbolt cables. Have we actually seen any indication of third party suppliers?

current Thunderbolt technology - which debuted today on Apple MacBook Pros – only works across a 3 metre cable. But according to (Intel's) Yogec and Ziller, Intel will eventually offer an optical cable that will plug into the existing on-system hardware, transferring data across much larger distances. "There's a variety of applications we've thought about [that require longer cables]," Ziller said. "For example, media creation, where you have long distances between video cameras and the machines they're connected to."

And eventually, the company says, it hopes to introduce an all-optical setup, where that optical transceiver sits on the PC. "We haven't abandoned the idea of a light connection," Ziller said. "We still believe that optics is in our future and will be necessary over time and will be brought in over time. We are still doing research and we will assess when its appropriate time is to bring that into the platform."

Frankly, the author of TFA needs to be slapped around for failure to understand the technology he's writing an article about.

What exactly don't I understand about the technology? The context of your comment seems to suggest that I don't know Thunderbolt will eventually use fiber. However, I mention it briefly in this article, and much more in the linked article I wrote about it when the tech was introduced: http://arst.ch/oda

Apparently, you (and quite a few others) don't seem to have any understanding of what a transceiver actually is. When you refer to a cable with built in transceivers as "having firmware in it" this becomes outright blatant.

Quote:

A transceiver is a device that has both a transmitter and a receiver which are combined and share common circuitry or a single housing.

The transceiver takes data from a device on one end of a connection and converts it into an electrical signal to be transmitted across copper (or a light signal to be sent across fiber). The transceiver on the other end receives the (electrical or optical) signal and converts it back into data for the device on the other end of the connection.

In modern ethernet, we are accustomed to using only one type of cable. Since only one type of cable is in use, we can have the transceiver be built into the ethernet jack on our devices itself.

This was not always the case with ethernet. Back when there were multiple choices for what type of cabling to use for ethernet, many computers had a single AUI (Attachment User Interface) port on the back to which you would attach external transceivers suitible for the multiple cable types in use at that time. (Coaxial Cable, Fiber, Twisted Pair). Then you would plug the cable in use at your business into that external transceiver.

You couldn't build the transceiver into the AUI port, because different types of cables have entirely different signaling properties and entirely different methods of attaching the transceiver to the cable.

With Thunderbolt, we are moving back to a system where the transceivers are not built into the jack itself. Thankfully, due to miniaturization, the transceivers can actually be built into the cable itself and not housed in separate devices this time.

If you note in the Register article linked above, Intel intends to ship an optical cable (with the required optical transceivers built in) that will plug into the exact same Thunderbolt port that exists on Macs today and be capable of very long cable runs that are simply impossible with copper.

Also note that Intel is fully aware that future versions of Thunderbolt will be too fast for copper to work at all, and when the time comes that only optical cabling will work, it intends to move the transceivers from the cable back into the device to take advantage of cost savings.

I suspect there will be options for breakout boxes that let you split off from ThunderBolt out to USB, Firewire, eSATA, ect. It could be very useful for people who need many more ports than their computer provides.

mr_lizard13 wrote:

"Thunderbolt may have a hard time gaining traction outside of the higher-end storage and video device market—a fate similar to Apple's FireWire."

I think Apple couldn't care less if the cable doesn't gain traction outside of the higher-end storage and video device market.

Apple are working to kill the concept of cables. Wireless syncing for iOS devices, AirDrop for sharing, AirPrint for printing, Time Capsule for wireless backup. And so on.

The list of things the normal user needs a cable for is shrinking. For the professional population who need a cable there's ThunderBolt.

Still, why bother getting potentially more expensive Thunderbolt devices if you're simply going to limit the throughput to approximately 1/10 of its potential speed by cheaping out on the cable?

Except at the moment I don't think any of us really knows if that is true or not. What would be educational would be to find out if Tb really does require active cabling in order to work, and if it doesn't, how much benefit active cabling truly is at 2 meter runs.

According to Intel, who developed the technology, it does. I suppose you could get a $1,000+ new Mac and a $2,000 RAID to test your theory, but I'm willing to take Intel's word for it. The active chips are also likely involved in the automatic switching between DisplayPort and PCIe signal output on the port.

I doubt it would be hard for these chips to measure the characteristics of any given cable and adapt accordingly, so they *could* be fitted to host devices integrally. So it really seems bogus to put them in the cables themselves. And, forgive me if I'm wrong, but if ethernet can carry 10GigE signalling without intergrated ICs in the cables then so could 'thunderbolt'. I smell a big putrid marketing rat...

WRT 10GB ethernet, I've worked with it some and there seem to be a few details that you are unaware of. Current 10GB ethernet runs over fibre, and above and beyond the cost of the 10GB ethernet HBA, you'll need a SFP at both ends. The SFPs have the integrated electronics, write lasers and read sensors. And last time I checked the 10GB ethernet HBA was over $1000 and if you need a 10GB switch you're looking in the $10,000 price range.

And I don't think you can use regular FC cables (not positive about this though), I think you'll need to buy 10GB fibre, and that alone probably costs more than the Apple cable.

So 10GB ethernet, while far more flexible, is still far more expensive than the Apple cable.

current Thunderbolt technology - which debuted today on Apple MacBook Pros – only works across a 3 metre cable. But according to (Intel's) Yogec and Ziller, Intel will eventually offer an optical cable that will plug into the existing on-system hardware, transferring data across much larger distances. "There's a variety of applications we've thought about [that require longer cables]," Ziller said. "For example, media creation, where you have long distances between video cameras and the machines they're connected to."

And eventually, the company says, it hopes to introduce an all-optical setup, where that optical transceiver sits on the PC. "We haven't abandoned the idea of a light connection," Ziller said. "We still believe that optics is in our future and will be necessary over time and will be brought in over time. We are still doing research and we will assess when its appropriate time is to bring that into the platform."

Frankly, the author of TFA needs to be slapped around for failure to understand the technology he's writing an article about.

What exactly don't I understand about the technology? The context of your comment seems to suggest that I don't know Thunderbolt will eventually use fiber. However, I mention it briefly in this article, and much more in the linked article I wrote about it when the tech was introduced: http://arst.ch/oda

Apparently, you (and quite a few others) don't understand what a transceiver is.

I guess if you're going to bother calling us idiots, you could do us all a favor and explain to us what transceivers (since we apparently don't know) are and how we are (I assume) misusing the word.

Still, why bother getting potentially more expensive Thunderbolt devices if you're simply going to limit the throughput to approximately 1/10 of its potential speed by cheaping out on the cable?

Except at the moment I don't think any of us really knows if that is true or not. What would be educational would be to find out if Tb really does require active cabling in order to work, and if it doesn't, how much benefit active cabling truly is at 2 meter runs.

According to Intel, who developed the technology, it does. I suppose you could get a $1,000 new Mac and a $2,000 RAID to test your theory, but I'm willing to take Intel's word for it. The active chips are also likely involved in the automatic switching between DisplayPort and PCIe signal output on the port.

They may be involved, but is it necessary that they be in the cable, instead of the devices simply handshaking with whatever's at the other end? Go back to the post you originally replied to, where the question is whether active cabling is necessary to truly make Thunderbolt work, or could it have been implemented with passive cabling for shorter runs/lower bandwidth and the active cabling reserved for the long runs/high bandwidth. Unless someone does the research or Intel comes clean, I guess we'll never know.

But since now we're assuming that active cable is required for all applications, the next big question is going to be whether Intel and/or Apple will permit third-party or unlicensed cables.

Because Intel presumably controls both. As of yet, they've not permitted third party TB chipsets, the only shipping TB chipsets are Intel parts in Apple devices, and the only manufacturer of TB cabling is TB partner Apple. You don't see a trend here yet?

Because Intel presumably controls both. As of yet, they've not permitted third party TB chipsets, the only shipping TB chipsets are Intel parts in Apple devices, and the only manufacturer of TB cabling is TB partner Apple. You don't see a trend here yet?

The peripherals need chipsets also. Or do those not count?

The pattern I'm seeing is "brand new technology has limited uptake". But, of course, why assume a simple answer when you can assume a conspiracy.

EDIT: Also, Intel has explicitly stated that Apple is not an exclusive licensee and that they do not want Apple to be the only licensee.

I still think the crime is that Apple didn't put USB3 on their current generation of products even as many large OEMs make it a standard feature. Apple charges a premium for their hardware so you'd think you would at least get all the current I/O ports.

When a $400 Vostro has USB3 and MBP doesn't... wtf. Are you going to carry around a TB cable and hub so you can use your external drive at full speed? Really?

USB3 is handy now... get a USB3 capable thumbdrive or put an SSD in an external enclosure and it is very nice step up.

Those bashing USB3 could stand to read up on it to - it offers proven 100MB throughput today and up to 400MB theoretical throughput in the future. http://www.techrepublic.com/blog/10thin ... nd-30/1265 or the like can be useful. For 99% of users this is going to be great - they'll be constrained by the ability of the destination disk to swallow the data.

Anyway, it looks good as a way to have some epic docking stations... as for cool external storage, they could have just started putting infiniband on Mac Pros and iMacs and called it good, right? If you're serious, as in really serious, about moving data around you probably are already connected to your SAN via Fiber Channel.

I was speaking of host chipsets. Presumably and obviously Intel is licensing device chipsets, otherwise there'd be no point.

Quote:

The pattern I'm seeing is "brand new technology has limited uptake". But, of course, why assume a simple answer when you can assume a conspiracy.

I'm not assuming a conspiracy, just noting that as of yet events have not shown that Thunderbolt cables will be permitted to manufactured by licensed or unlicensed third parties, history has not shown that Intel has been forthcoming with licenses for host chipsets, and Apple itself has a history of tightly controlling the dongles and devices that connect to their machines (iPod/iPhone docks and connectors) edit (continued): This is all presented mainly as a rebuttal to the assumption by many that TB host chipsets and cables will end quickly be commoditized Monoprice-style. As of yet, events just don't indicate that either Intel or Apple are interested in that happening.

Quote:

EDIT: Also, Intel has explicitly stated that Apple is not an exclusive licensee and that they do not want Apple to be the only licensee.

For cables, or host devices? Intel has said before that they were willing to allow other licensees for host chipsets, but so far there's either been no takers or they haven't met Intel's approval.

current Thunderbolt technology - which debuted today on Apple MacBook Pros – only works across a 3 metre cable. But according to (Intel's) Yogec and Ziller, Intel will eventually offer an optical cable that will plug into the existing on-system hardware, transferring data across much larger distances. "There's a variety of applications we've thought about [that require longer cables]," Ziller said. "For example, media creation, where you have long distances between video cameras and the machines they're connected to."

And eventually, the company says, it hopes to introduce an all-optical setup, where that optical transceiver sits on the PC. "We haven't abandoned the idea of a light connection," Ziller said. "We still believe that optics is in our future and will be necessary over time and will be brought in over time. We are still doing research and we will assess when its appropriate time is to bring that into the platform."

Frankly, the author of TFA needs to be slapped around for failure to understand the technology he's writing an article about.

What exactly don't I understand about the technology? The context of your comment seems to suggest that I don't know Thunderbolt will eventually use fiber. However, I mention it briefly in this article, and much more in the linked article I wrote about it when the tech was introduced: http://arst.ch/oda

Apparently, you (and quite a few others) don't understand what a transceiver is.

I guess if you're going to bother calling us idiots, you could do us all a favor and explain to us what transceivers (since we apparently don't know) are and how we are (I assume) misusing the word.

Already done, recheck the post above.

Also, what's the deal with taking away the buttons for adding things like quotes and url's from the comments section of the article? I end up posting a comment to the article there and then having to log into civis, find that thread and then edit the comment when I need to add quotes, images, etc.

Still, why bother getting potentially more expensive Thunderbolt devices if you're simply going to limit the throughput to approximately 1/10 of its potential speed by cheaping out on the cable?

Except at the moment I don't think any of us really knows if that is true or not. What would be educational would be to find out if Tb really does require active cabling in order to work, and if it doesn't, how much benefit active cabling truly is at 2 meter runs.

According to Intel, who developed the technology, it does. I suppose you could get a $1,000 new Mac and a $2,000 RAID to test your theory, but I'm willing to take Intel's word for it. The active chips are also likely involved in the automatic switching between DisplayPort and PCIe signal output on the port.

They may be involved, but is it necessary that they be in the cable, instead of the devices simply handshaking with whatever's at the other end? Go back to the post you originally replied to, where the question is whether active cabling is necessary to truly make Thunderbolt work, or could it have been implemented with passive cabling for shorter runs/lower bandwidth and the active cabling reserved for the long runs/high bandwidth. Unless someone does the research or Intel comes clean, I guess we'll never know.

The experts I have spoken to all agree that active cabling is required, even at 2m for the bitrates involved. I agree it seems plausible that it could be made to work at a lower data rate with passive cables, but as others have mentioned, why bother with that if eSATA or USB3 would otherwise suffice?

AnandTech has a Promise RAID they have been testing, and have achieved transfer rates of nearly 700MB/s. That doesn't saturate the 1.25GB/s maximum, which is likely due to limitations of the RAID hardware itself as Intel has demonstrated that Tb can transfer data at its full rated speed. But it does transfer at nearly twice the speed of comparable USB3 devices.

Quote:

But since now we're assuming that active cable is required for all applications, the next big question is going to be whether Intel and/or Apple will permit third-party or unlicensed cables.

As best as can be determined, that's up to Intel to decide (not Apple), but it seems unlikely that it wouldn't license the specs to other manufacturers. From what I've heard, they just haven't released the specs, though they were expected to around this time.

What I think the problem is with Apple being the only supplier right now, though, isn't necessarily price, but the fact that mobo makers, as well as Dell, Lenovo, HP et al are looking at this and thinking, "If you can only get cables from Apple, why would we want to put Tb on our computers?"

current Thunderbolt technology - which debuted today on Apple MacBook Pros – only works across a 3 metre cable. But according to (Intel's) Yogec and Ziller, Intel will eventually offer an optical cable that will plug into the existing on-system hardware, transferring data across much larger distances. "There's a variety of applications we've thought about [that require longer cables]," Ziller said. "For example, media creation, where you have long distances between video cameras and the machines they're connected to."

And eventually, the company says, it hopes to introduce an all-optical setup, where that optical transceiver sits on the PC. "We haven't abandoned the idea of a light connection," Ziller said. "We still believe that optics is in our future and will be necessary over time and will be brought in over time. We are still doing research and we will assess when its appropriate time is to bring that into the platform."

Frankly, the author of TFA needs to be slapped around for failure to understand the technology he's writing an article about.

What exactly don't I understand about the technology? The context of your comment seems to suggest that I don't know Thunderbolt will eventually use fiber. However, I mention it briefly in this article, and much more in the linked article I wrote about it when the tech was introduced: http://arst.ch/oda

Apparently, you (and quite a few others) don't understand what a transceiver is.

I guess if you're going to bother calling us idiots, you could do us all a favor and explain to us what transceivers (since we apparently don't know) are and how we are (I assume) misusing the word.

Already done, recheck the post above.

As I already pointed out, linking to some other post from the Register in no way explains a) why you think I don't know what a transceiver is (I do), and b) why I don't understand how Thunderbolt works. Did I make some factual error? Did I use the word transceiver incorrectly? If you're referring to the part about Thunderbolt using optical connections in future iterations—which appears to be bolded in the text you quoted, though FWIW you can only see that if you are reading on civis or look for the BBCode—I'm already well aware of that fact. How does that relate to your assertion that I don't know what I'm talking about?

I'm still not sure if you're just trying to be smug and claim we're all stupid or if you actually want us to understand some critical point and just aren't doing a very good job of explaining what that point is.

EDIT: I see that you extensively edited your earlier post, so I didn't see your additional explanation. However, this quote is not from me:

Quote:

When you refer to a cable with built in transceivers as "having firmware in it" this becomes outright blatant.

I never referred to it that way; that it what Promise's support technician told us (as explcitly stated in the article text). We knew right away that was pretty much a bullshit explanation, which is why we teamed up with iFixit to find out exactly what was inside the cable.

As far as you continuing to act like I never knew that Thunderbolt would use optical cabling, I've repeatedly mentioned that fact, as well as linking to my original article from 4 months ago when I discussed that very topic.

The experts I have spoken to all agree that active cabling is required, even at 2m for the bitrates involved. I agree it seems plausible that it could be made to work at a lower data rate with passive cables, but as others have mentioned, why bother with that if eSATA or USB3 would otherwise suffice?

Because it gets your technology out into the market without requiring a 50 dollar active cable. So I guess we can presume that an active cable is a fundamental requirement at all lengths and speeds, or that Intel and/or Apple is willing to accept the initial hit to adoption to insure that all devices can operate at the speeds advertised.

Quote:

AnandTech has a Promise RAID they have been testing, and have achieved transfer rates of nearly 700MB/s. That doesn't saturate the 1.25GB/s maximum, which is likely due to limitations of the RAID hardware itself as Intel has demonstrated that Tb can transfer data at its full rated speed. But it does transfer at nearly twice the speed of comparable USB3 devices.

And for that kind of device an active cable isn't a big deal. The argument is whether, if possible, it would have been better for Thunderbolt to allow passive cables for slower and cheaper devices simply to encourage penetration.

Quote:

What I think the problem is with Apple being the only supplier right now, though, isn't necessarily price, but the fact that mobo makers, as well as Dell, Lenovo, HP et al are looking at this and thinking, "If you can only get cables from Apple, why would we want to put Tb on our computers?"

Which makes me curious why Intel has been so quiet up to this point about the cabling issue. How is it that this seems to have caught everyone by surprise? I don't think it was mentioned at all at the Thunderbolt reveal or when the new Thunderbolt equipped Macs were released.

I already clarified that I meant the host chipsets. What's still at question is the licensing process for the cables. Just because Gennum makes the transceivers in the cables doesn't mean that they are licensed to make the whole cable, or licensed to do so for anyone but Apple, or whether and how any other companies will be permitted to do so.

As I already pointed out, linking to some other post from the Register in no way explains a) why you think I don't know what a transceiver is (I do), and b) why I don't understand how Thunderbolt works. Did I make some factual error? Did I use the word transceiver incorrectly? If you're referring to the part about Thunderbolt using optical connections in future iterations—which appears to be bolded in the text you quoted, though FWIW you can only see that if you are reading on civis or look for the BBCode—I'm already well aware of that fact. How does that relate to your assertion that I don't know what I'm talking about?

I'm still not sure if you're just trying to be smug and claim we're all stupid or if you actually want us to understand some critical point and just aren't doing a very good job of explaining what that point is.

Dude, you just wrote an article calling a transceiver "firmware". Obviously you don't know what they are.

The entire point of cables with integrated transceivers was to allow electrical or optical versions of thunderbolt cables to attach to the exact same Thunderbolt port. Intel has made this perfectly clear to the press in the past, as the linked Register article shows.

The experts I have spoken to all agree that active cabling is required, even at 2m for the bitrates involved. I agree it seems plausible that it could be made to work at a lower data rate with passive cables, but as others have mentioned, why bother with that if eSATA or USB3 would otherwise suffice?

Someone needs to tell Infiniband that their passive 10 Gbps per channel 10-meter cables are impossible. And the same story should be told to the folks at IEEE that are developing the 100 Gbps system (10 channels of 10 Gbps) intended to run over 10 meter passive cables. All those systems are capatible with active cables (for runs greater than 10 up to about 100 meters) and optical cables (for runs like 1 km). I don't know what experts you have spoken with but the reality is that with a slightly larger diameter conductor, a 2 meters cable could easily be passive at 10 Gbps or even 20 Gbps (silicon is still be developed for this so just the cable would be available). For faster data rates you would simply have to encode (that would get you to at least 40 Gbps). Frankly, any talk about active cables being required is unsupportable. If you prefer that design direction, fine. But to say that it is required, not supportable.

Somebody hasn't priced out 10 gig ethernet cables and transceivers lately. $50 is a bargain by comparison -- especially if you add in the cost of a switch. Even copper SAS and fibre channel cables are expensive and they top out at 6 and 8 gig respectively.

Dude, you just wrote an article calling a transceiver "firmware". Obviously you don't know what they are.

The entire point of cables with integrated transceivers was to allow electrical or optical versions of thunderbolt cables to attach to the exact same Thunderbolt port. Intel has made this perfectly clear to the press in the past, as the linked Register article shows.

Do a little research before you write and when someone points out an error, try being graceful. Have you ever noticed what happens when one of Anandtech's readers points out a factual error?

Anand thanks them and then makes a correction.

Your lack of comprehension is epic. It's not Chris calling it "firmware", it's the Promise rep he contacted on the phone, as indicated by the quotes. Chris goes on just a few paragraphs later to clarify that they are transceivers and describe their exact function, with quotes directly from Gennum. Then you have the temerity to imply that he's the one that's incorrect...

The experts I have spoken to all agree that active cabling is required, even at 2m for the bitrates involved. I agree it seems plausible that it could be made to work at a lower data rate with passive cables, but as others have mentioned, why bother with that if eSATA or USB3 would otherwise suffice?

Because it gets your technology out into the market without requiring a 50 dollar active cable. So I guess we can presume that an active cable is a fundamental requirement at all lengths and speeds, or that Intel and/or Apple is willing to accept the initial hit to adoption to insure that all devices can operate at the speeds advertised.

I agree with your conclusion there.

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AnandTech has a Promise RAID they have been testing, and have achieved transfer rates of nearly 700MB/s. That doesn't saturate the 1.25GB/s maximum, which is likely due to limitations of the RAID hardware itself as Intel has demonstrated that Tb can transfer data at its full rated speed. But it does transfer at nearly twice the speed of comparable USB3 devices.

And for that kind of device an active cable isn't a big deal. The argument is whether, if possible, it would have been better for Thunderbolt to allow passive cables for slower and cheaper devices simply to encourage penetration.

That makes sense; but I think if that was the tack Intel and Apple had taken one or both of these outcomes would have been likely:1. Thunderbolt would be harder to use, making sure you have the right cables for the right devices, etc. I think FireWire, with IEEE1394/i.Link, FW400, and FW800 suffers from this problem to some degree, though the original promise was that it would be this single standard port. Even USB, really, with all it's mini and micro variations, UBB3 having a completely different B plug, etc, is as bad or worse. Maybe not SCSI bad, but it's friction that doesn't necessarily need to be there. Thunderbolt port = Thunderbolt cable, even though you can have optical and electrical variations, simplifies things significantly, I think.

2. Having slower speeds with passive cables would amplify the "Why not just use USB3?" crowd.

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What I think the problem is with Apple being the only supplier right now, though, isn't necessarily price, but the fact that mobo makers, as well as Dell, Lenovo, HP et al are looking at this and thinking, "If you can only get cables from Apple, why would we want to put Tb on our computers?"

Which makes me curious why Intel has been so quiet up to this point about the cabling issue. How is it that this seems to have caught everyone by surprise? I don't think it was mentioned at all at the Thunderbolt reveal or when the new Thunderbolt equipped Macs were released.

I don't know, exactly. Intel discussed the fact that it was going to use active cabling months ago. But when we mentioned that Apple was selling a $49 cable on Tuesday, commenters were flipping their lids.

No he didn't. Stop bullshitting and just admit you're wrong. Or at least go away. You're too uninformed to be posting in this thread.

BullBearMS wrote:

The entire point of cables with integrated transceivers was to allow electrical or optical versions of thunderbolt cables to attach to the exact same Thunderbolt port. Intel has made this perfectly clear to the press in the past, as the linked Register article shows.

There are other advantages even for non optical systems. See for example, active vs. passive display port.

BullBearMS wrote:

Do a little research before you write and when someone points out an error, try being graceful. Have you ever noticed what happens when one of Anandtech's readers points out a factual error?

They explode about how global warming isn't real and we're all just sheep for believing in it? That would be my favorite memory of Anandtech's editorial team at work anyway.

As an aside, I am not convinced that DisplayPort is a good design for data rates much higher than 10 Gbps so it is more likely than not that a different interface is going to be used for the 20 and 40 Gbps versions. And if that is the case, it makes the use of active cables even less supportable. Beef up the wire a little and give us a cheap $15-$20 cable.

I already clarified that I meant the host chipsets. What's still at question is the licensing process for the cables. Just because Gennum makes the transceivers in the cables doesn't mean that they are licensed to make the whole cable, or licensed to do so for anyone but Apple, or whether and how any other companies will be permitted to do so.

After Intel put an end to others being allowed to produce PC chipsets compatible with Intel CPU's, you can't put anything past them.

When you introduce something as a "standard" and put retarded restrictions on said standard, we know what happens. Firewire. Even after the retarded restrictions were completely removed, it never came into it's own.

I'd say that these cables are single sourced right now because they want to make sure there aren't any problems during the technology's roll out. I imagine quality control is extremely tight.

Somebody hasn't priced out 10 gig ethernet cables and transceivers lately. $50 is a bargain by comparison -- especially if you add in the cost of a switch. Even copper SAS and fibre channel cables are expensive and they top out at 6 and 8 gig respectively.

Newegg has Cat6A cables for ~$2.50 for 6 feet. NICs are ~$500, but Intel has gone on record that the cost of the TB silicon is commensurate with other 10Gb solutions, 10GBASE-T NICs are still predominantly a high-margin server part, and we don't know what kind of margins, or even losses, if any, Apple are taking by including TB.

That makes sense; but I think if that was the tack Intel and Apple had taken one or both of these outcomes would have been likely:1. Thunderbolt would be harder to use, making sure you have the right cables for the right devices, etc. I think FireWire, with IEEE1394/i.Link, FW400, and FW800 suffers from this problem to some degree, though the original promise was that it would be this single standard port. Even USB, really, with all it's mini and micro variations, UBB3 having a completely different B plug, etc, is as bad or worse. Maybe not SCSI bad, but it's friction that doesn't necessarily need to be there. Thunderbolt port = Thunderbolt cable, even though you can have optical and electrical variations, simplifies things significantly, I think.

I don't see how that follows. Both active and passive cables can use the same port, you only need to worry about having an active cable if your device requires it, and if you're in that market, you're not likely to get caught out by that, especially if manufacturer puts it right on the product page/box lid.

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2. Having slower speeds with passive cables would amplify the "Why not just use USB3?" crowd.

Yeah but you can't make USB go faster just by using a different cable.

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I don't know, exactly. Intel discussed the fact that it was going to use active cabling months ago. But when we mentioned that Apple was selling a $49 cable on Tuesday, commenters were flipping their lids.

Dude, you just wrote an article calling a transceiver "firmware". Obviously you don't know what they are.

The entire point of cables with integrated transceivers was to allow electrical or optical versions of thunderbolt cables to attach to the exact same Thunderbolt port. Intel has made this perfectly clear to the press in the past, as the linked Register article shows.

Do a little research before you write and when someone points out an error, try being graceful. Have you ever noticed what happens when one of Anandtech's readers points out a factual error?

Anand thanks them and then makes a correction.

Your lack of comprehension is epic. It's not Chris calling it "firmware", it's the Promise rep he contacted on the phone, as indicated by the quotes. Chris goes on just a few paragraphs later to clarify that they are transceivers and describe their exact function, with quotes directly from Gennum. Then you have the temerity to imply that he's the one that's incorrect...

The Promise rep didn't write the article.

When you are writing an article about why a cable costs 50 bucks, you probably should mention that unlike the cables readers are familiar with, these cables include the cost of integrated transceivers. Don't just call them "active cables" without understanding or explaining what an active cable is.

You might want to go on to mention that the reason for including the transceiver in the cable itself is to give you the flexibility of having optical cables that can plug into the exact same physical port.

Which is why Chris put their description in quotes, and then went looking for a better one, which he got both from industry experts and the manufacturer of the chips in question. Or didn't you read that part?

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When you are writing an article about why a cable costs 50 bucks, you probably should mention that unlike the cables readers are familiar with, these cables include the cost of integrated transceivers.

I think we can all take as a given that the cost of a product includes the cost of all of its parts, and in fact the topic of the entire article is to examine why exactly the part costs what it does.

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Don't just call them "active cables" without understanding or explaining what an active cable is.

You might want to go on to mention that the reason for including the transceiver in the cable itself is to give you the flexibility of having optical cables that can plug into the exact same physical port.

Seems to me he did exactly that, in the very same article we're commenting on, though to be truthful there's nothing preventing a passive copper cable and an active optical cable from using the same interface.

The experts I have spoken to all agree that active cabling is required, even at 2m for the bitrates involved. I agree it seems plausible that it could be made to work at a lower data rate with passive cables, but as others have mentioned, why bother with that if eSATA or USB3 would otherwise suffice?

Someone needs to tell Infiniband that their passive 10 Gbps per channel 10-meter cables are impossible. And the same story should be told to the folks at IEEE that are developing the 100 Gbps system (10 channels of 10 Gbps) intended to run over 10 meter passive cables. All those systems are capatible with active cables (for runs greater than 10 up to about 100 meters) and optical cables (for runs like 1 km). I don't know what experts you have spoken with but the reality is that with a slightly larger diameter conductor, a 2 meters cable could easily be passive at 10 Gbps or even 20 Gbps (silicon is still be developed for this so just the cable would be available). For faster data rates you would simply have to encode (that would get you to at least 40 Gbps). Frankly, any talk about active cables being required is unsupportable. If you prefer that design direction, fine. But to say that it is required, not supportable.

edited.

I won't argue the theoretical here, but you're right that maybe the word "required" is too strong. I'll merely state that active cables are far more common at these data rates and definitely with the gauge of cabling being used.

I've heard about the 10Gbps system that has been proposed, but it does not exist today, as you mentioned. As far as InfiniBand cables... how much do those cost again? And how many channels can a single cable carry?

Somebody hasn't priced out 10 gig ethernet cables and transceivers lately. $50 is a bargain by comparison -- especially if you add in the cost of a switch. Even copper SAS and fibre channel cables are expensive and they top out at 6 and 8 gig respectively.

Newegg has Cat6A cables for ~$2.50 for 6 feet. NICs are ~$500, but Intel has gone on record that the cost of the TB silicon is commensurate with other 10Gb solutions, 10GBASE-T NICs are still predominantly a high-margin server part, and we don't know what kind of margins, or even losses, if any, Apple are taking by including TB.

You are talking about a cable that does not include or require integrated transceivers. The transceiver is included in the $500 price of the NIC.

Look, let's price currently made external optical transceivers for modern ethernet standards.

Here's a one Gigabit external transceiver:

Here's a ten Gigabit external transceiver:

When you roll the price of two transceivers into the price of the cable, costs are going to have to go up. Luckily, they don't go up anywhere near this much.

Still, we haven't yet seen how much Intel is going to charge for their Thunderbolt fiber optic cable. They have the technology to make a single chip optical transceiver, so it won't start out as two times 2000 bucks as is the case for the ten gigabit transceiver above, but I'm sure it will make fifty bucks look very cheap in comparison.